The purpose of this project is to establish the feasibility for a new concept of measuring sweat and urine osmolarity. This measurement is valuable as an aid in identifying cystic fibrosis in infants and also for monitoring salt intake in hypertensive individuals. Both of these tests are commercially desirable. This test is based on a proven but proprietary method that employs an osmolarity-sensitive reactant and a special dye which changes color in response to samll changes in ionic strength. A qualitative and a semi-quantitative test are envisioned for Phase II--as simple and as easily read as currently available pH dip stick tests. Phase I of the proposed project is a survey and an identification of the best combination of reactant and dye; then, testing of their performance under controlled conditions using the normal levels of the electrolytes found in sweat and urine will be performed. Once a working liquid formulation is discovered, the reagents will be dried in a film or on paper for potential use in a dip stick or slide-type arrangement.